<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>1-引出生命周期</title>
</head>

<body>
    <!-- 准备好一个容器 -->
    <div id="test"></div>
    <!-- 引入react核心库 -->
    <script type="text/javascript" src="../js/react.development.js"></script>
    <!-- 引入react-dom，用于支持react操作DOM -->
    <script type="text/javascript" src="../js/react-dom.development.js"></script>
    <!-- 引入babel，用于将jsx转换为js -->
    <script type="text/javascript" src="../js/babel.min.js"></script>

    <script type="text/babel">  //此处一定要写babel
        //创建组件
        //生命周期回调函数   <=> 生命周期钩子函数 <=> 生命周期函数 <=> 生命周期钩子
        class Life extends React.Component {

            state = { opacity: 1 }

            death = () => {

                //卸载组件
                ReactDOM.unmountComponentAtNode(document.querySelector('#test'));
            }

            // action = () => {
            //     setInterval(() => {
            //         //获取原状态
            //         let opacity = this.state.opacity;
            //         //减少0.1
            //         opacity -= 0.1;
            //         if (opacity <= 0) opacity = 1;
            //         //设置新的透明度
            //         this.setState({ opacity })
            //     }, 200)
            // }

            //组件挂载完毕
            componentDidMount() {
                this.timer = setInterval(() => {
                    //获取原状态
                    let opacity = this.state.opacity;
                    //减少0.1
                    opacity -= 0.1;
                    if (opacity <= 0) opacity = 1;
                    //设置新的透明度
                    this.setState({ opacity })
                }, 200)
            }


            //组件将要卸载
            componentWillUnmount() {
                //清除定时器
                clearInterval(this.timer)
            }

            //render调用的时机，初始化渲染、状态更新之后
            render() {
                console.log('render');
                return (
                    <div>
                        <h2 style={{ opacity: this.state.opacity }}>React学不会怎么办?</h2>
                        <button onClick={this.death}>不活了</button>

                    </div>
                )
            }
        }

        //渲染组件
        ReactDOM.render(<Life />, document.querySelector('#test'));
    </script>
</body>

</html>